The diatonic harmonica
The diatonic harmonica is most likely what you think of when you think
of a "harmonica." It has ten holes which offer the player 19 notes
(10 holes times a draw and a blow for each hole minus one repeated
note) in a three octave range. The standard diatonic harmonica is
designed to allow a player to play chords and melody in a single key.
Because they are only designed to be played in a single key at a time,
diatonic harmonicas are available in all keys. Here is a standard
diatonic harmonica's layout in the key of C (1 blow is middle C):
1 2 3 4 5 6 7 8 9 10
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blow: |C |E |G |C |E |G |C |E |G |C |
draw: |D |G |B |D |F |A |B |D |F |A |
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Note that although there are 3 octaves between 1 and 10 blow, there is only one full major scale available on the harmonica, between holes 4 and 7. The lower holes are designed around the tonic (C major) and dominant (G major) chords, allowing a player to play these chords underneath a melody by blocking or unblocking the lower holes with the tongue.
In addition to the 19 notes readily available on the harmonica,
players can play other notes by adjusting their embouchure and forcing
the reed to resonate at a different pitch. This technique is
called "bending", a term borrowed from guitarists, who literally "bend" a string in order to create subtle changes in pitch. Using bending, a player can reach all the notes on the
major scale. "Bending" also creates the glissandos
characteristic of much blues and country harmonica playing.
The physics of bending are quite complex, but amount to this: a player can
bend the pitch of the higher-tuned reed down toward the pitch of the lower-tuned reed in any given hole. In other words, on holes 1 through 6, the draw notes can be bent and on holes 7 through 10 the blow notes can be bent. Hole 3 allows for the most dramatic bending: in C, it is possible to bend 3 draw from a B down to a G#, or anywhere in between.
Howard Levy developed another technique in the 1970s that allows players
to force a reed to vibrate faster, resulting in a higher pitch. This
technique is called overblowing or overdrawing and is much
less frequently used. For the few who master this technique, the
diatonic harmonica can function as a fully chromatic instrument.
List of Modern Overblow Masters:
- Howard Levy
- Chris Michalek
- Joe Filisko
- Michael Peloquin
- Rosco Selley
- George Brooks
- Larry Eisenberg
- Sandy Weltman
- Greg Szlapczynski
Special tuned harmonicas
The Hohner Marine Band 1896 14 hole harmonica is not a standard diatonic harmonica. It has 14 holes and its general dimensions are a bit bigger, so its structure is different from the normal diatonic harmonica and it is pitched one octave lower than the standard 10 hole diatonic. Thus, hole 4 blow is one octave below middle C. Hole 7 blow is middle C. Holes 1 through 4 and 6 are draw bendable, and holes 8 through 14 are blow bendable.
1 2 3 4 5 6 7 8 9 10 11 12 13 14
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blow: |C |E |G |C |E |G |C |E |G |C |E |G |C |E |
draw: |D |G |B |D |F |A |B |D |F |A |B |D |F |A |
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